Unnamed until the third movie, Izayoi was a human who fell in love with Inutaishou. It was because of his feelings for his wife and his desire to protect her that Inutaishou had the Tessaiga forged. Izayoi was gentle and kind-hearted, and the only person Inuyasha knew before Kagome that accepted him for who he was.

Her looks were fairly generic for princesses in the series, and she's shown wearing rich clothes. Izayoi died while Inuyasha was still young, of an unknown cause. Most people assume it was a natural illness, though it has never been stated one way or the other.